Multimode interference waveguides are favored for their wide bandwidth, extensive fabrication tolerance, high stability, effective light confinement, and minimal transmission loss. In this study, we propose a numerical design of an optical power splitter based on restricted interference mechanisms using silicon-on-insulator waveguides, where the precise positioning of input pairs and subsequent adjustment of the multimode interference (MMI) region length are essential aspects. The RI-MMI configuration facilitates the reduction of the MMI length due to the applied interference theory. Our design undergoes rigorous simulation and optimization using the highly accurate 3D-BPM simulation method to ensure optimal performance. Simulation results confirm our high-performance design with low excess loss (<2.7 dB), small relative phase difference (<2%), negligible residual (<-18 dB), excellent coupling ratio (-0.09 dB to 0.05 dB), and a high balance factor (<-17 dB) across a wide range of 100 nm (1500 nm – 1600 nm). Furthermore, our optimized design exhibits a width tolerance of ±2.1 µm and a height tolerance of ±10 nm. Notably, the core component of the splitter is housed within an extremely compact footprint area of 6 µm × 65 µm. These exceptional characteristics position our proposed device as highly promising for large-scale integrated optical circuits as well as photonic neural networks in ultrawideband telecom applications.